Featured Research

from universities, journals, and other organizations

Polish Dumpling-Like Particle Has Potential In Drug Delivery

Date:

May 22, 1998

Source:

Washington University In St. Louis

Summary:

Chemists at Washington University in St. Louis have created synthetic polymer particles that are as cute as dumplings. They're called knedels (k-ned-l), after a popular Polish dumpling filled either with meat or sweets. While the Polish knedel is a sumptuous taste treat, the Washington University knedl is a synthetic nano-sized particle that its creators hope someday will be the carrier of drugs or genes for biomedical applications and therapies.

Related Articles

They're called knedels (k-ned-l), after a popular Polish dumpling filled either with meat or sweets. While the Polish knedel is a sumptuous taste treat, the Washington University knedl is a synthetic nano-sized particle that its creators hope someday will be the carrier of drugs or genes for biomedical applications and therapies.

Karen Wooley, Ph.D., assistant professor of chemistry at Washington University, recently announced a new breakthrough in the particle that K. Bruce Thurmond, II, a graduate student in Wooley's group, first synthesized in 1996. Wooley and post-doctoral researcher Haiyong Huang, Ph.D., have changed the composition of their knedel's core from a glassy to a rubbery substance similar to the interior of a golf ball. Additionally, this core can be hollowed out, creating a capsule into which large amounts of drugs -- or DNA, for gene therapy -- may be loaded for delivery.

Huang presented a talk on the advance at the Spring Meeting of the American Chemical Society, March 29, in Dallas, TX.

"They're like golf ball molecules in this form" says Wooley. "This advance moves us along in our goal of making knedels potential drug- and gene- carrying systems. It makes the particle a lot more versatile and the rubbery core should allow a higher loading capacity We've gotten lots of interest in the knedels, for their potential, they're novelty, and their name."

The work is funded by the National Science Foundation and Monsanto Company, St. Louis.

Wooley and her colleagues recently have been focusing on the knedel's water-soluble shell that allows them to bind DNA to its surface. This in turn causes small aggregates to form that protect the genetic material from being digested by enzymes. The chemists charge the shell positively so the knedel attracts DNA, which has a negative charge. Thus, the shell itself can play a key role in drug delivery.

Knedels are variations and improvements on a class of polymers -- chain-like structures of repeating compound assemblies -- called micelles. There has been lots of interest this decade in micelles for drug delivery, but they have a major drawback for this purpose. They are dynamic and unstable. If they are diluted or subjected to force in a system, they tend to fall apart.

Knedels, on the other hand, assemble and behave much the way proteins such as insulin do. With insulin, which our pancreas secrete to regulate our blood sugar rates, there are two linear polymer chains of amino acids -- the chemical units that are the building blocks of proteins. The linear chains self-assemble into a three-dimensional structure stabilized by linking with chemical bonds between two residues of amino acids. These cross-linkings hold everything together.

The knedel is constructed in a similar fashion. Wooley and her colleagues form a polymer micelle composed of as few as 10 to several hundred chains, assembled into a glassy sphere with a core that does not mix with the shell or the outer environment. Chemical reactions within the shell bind the chains together and give the stabilized, cross-linked structure.

"The knedel is a very simple approach that offers versatility for composition of the particles," she says. "We can control the size of the core, the thickness of the shell and the overall size of particles as well as the core and shell compositions. This will enable us to control the properties and function of the particles in their environment."

Originally Wooley and her group placed polystyrene -- the basic stuff of which disposable coffee cups are made -- into the core, but found it was too inflexible. They could not place material into the core unless a solvent was used. The new core is made of a more flexible material, polyisoprene, which has cross-linking capabilities that give the structure its rubbery property.

Wooley has future plans of incorporating degradable polymers into the knedel structure. She and graduate students Jennifer Weinberg and Min Wang have developed new degradable polymers that they can time to fall apart in water anywhere from a few minutes to a few months. Adding this feature to a drug-bearing knedel would give the particle the ability to be time-released.

Wooley also is working on modifications to the knedel's shell. She wants to make it flexible so that when it comes into contact with proteins, the shell won't cause proteins to stick and denature, which is an altering of molecular structure.

As for that name: After Wooley and her group constructed the polymer particles, they tried to see them with a standard electron microscope, but the particles were too small. They turned to colleague Tomasz Kowalewski, Ph.D., research assistant professor of chemistry at Washington University, a Polish native who is an expert in atomic force microscopy (AFM), and operates one at Washington University. This microscope is a new, powerful tool that can visualize nature's tiniest objects.

"Tomasz said, 'Oh, they look like knedels. You must call them that', And that's how they got their name," Wooley says.

Washington University In St. Louis. "Polish Dumpling-Like Particle Has Potential In Drug Delivery." ScienceDaily. ScienceDaily, 22 May 1998. <www.sciencedaily.com/releases/1998/05/980522082239.htm>.

Washington University In St. Louis. (1998, May 22). Polish Dumpling-Like Particle Has Potential In Drug Delivery. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/1998/05/980522082239.htm

Washington University In St. Louis. "Polish Dumpling-Like Particle Has Potential In Drug Delivery." ScienceDaily. www.sciencedaily.com/releases/1998/05/980522082239.htm (accessed March 31, 2015).

More From ScienceDaily

More Matter & Energy News

Featured Research

Mar. 31, 2015 — Landfills can make a profit from all their rotting waste and a new patent explains exactly how to make the most out of the stinky garbage sites. Decomposing trash produces methane, a landfill gas ... full story

Mar. 31, 2015 — Scientists have achieved an unprecedented level of control over defects in liquid crystals that can be engineered for applications in liquid matter photonics. Sitting with a joystick in the comfort ... full story

Mar. 30, 2015 — Neuroscientists are taking inspiration from natural motor control to design new prosthetic devices that can better replace limb function. Researchers have tested a range of brain-controlled devices ... full story

Mar. 30, 2015 — Speaking in public is the top fear for many people. Now, researchers have developed an intelligent user interface for 'smart glasses' that gives real-time feedback to the speaker on volume modulation ... full story

Mar. 30, 2015 — By studying the morphology and physiology of plants with tiny conical "hairs" or microfibers on the surface of their leaves, such as tomatoes, balsam pears and the flowers Berkheya purpea and Lychnis ... full story

Mar. 30, 2015 — In the first study of its kind, scientists quantitatively show that electric vehicles will meet the daily travel needs of drivers longer than commonly assumed. They found that batteries that have ... full story

Mar. 30, 2015 — As the demand for instant, constant communication grows, so too does the urgency for more convenient portable devices -- especially computer displays that can be easily rolled up and stored or ... full story

Mar. 30, 2015 — There are electrical signals in the nervous system, the brain and throughout the human body and there are tiny magnetic fields associated with these signals that could be important for medical ... full story

Mar. 30, 2015 — Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice. The researchers hope their nanoneedle technique could ... full story

Bionic Ants Could Be Tomorrow's Factory Workers

Reuters - Innovations Video Online (Mar. 30, 2015) — Industrious 3D printed bionic ants working together could toil in the factories of the future, says German technology company Festo. The robotic insects cooperate and coordinate their actions and movements to achieve a common aim. Amy Pollock reports.
Video provided by Reuters

Related Stories

July 12, 2013 — Researchers have developed an efficient system to coat tiny objects, such as bacterial cells, with thin films that assemble themselves which could have important implications for drug delivery as ... full story

Dec. 19, 2012 — Scientists have succeeded in organizing virus particles, protein cages and nanoparticles into crystalline materials. These nanomaterials are important for applications in sensing, optics, electronics ... full story

June 15, 2010 — Dutch researchers have successfully converted a virus into a unique drug distributor. They removed all of the dangerous material from the virus so that empty, semipermeable particles remained. They ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.